In recent years, computers that execute an operating system (OS) program that achieves multitasking are widely used. The multitasking is a function of causing a single computer to simultaneously execute multiple programs such as application software in parallel. As a method for achieving the multitasking, there is a method for causing an OS to provide execution priorities to programs on the basis of degrees of importance of the programs, degrees of urgency of the programs, or the like and selecting a program to be executed on the basis of the provided execution priorities, for example.
Another technique for controlling a priority is described below. For example, there is a technique for repeatedly executing a control processing application program on a priority basis over an information processing application program for one cycle, executing control processing, stopping the execution of the control processing application program by the execution of a stop command for a certain time period, and executing the information processing application program.
In addition, there is a technique for measuring a load that is to be applied to an electronic computer for a certain time period and is a criterion to determine priority switching when the electronic computer tries to automatically switch a priority, determining the timing of the switching, and thereby quickly executing a selected man machine interface process even when a high load is applied to the electronic computer. The techniques are disclosed in Japanese Laid-open Patent Publication Nos. 9-251389 and 9-138702, for example.